Abstract
Hierarchical Cu-Al(2)O(3)/biomass-activated carbon composites were successfully prepared by entrapping a biomass-activated carbon powder derived from green algae in the Cu-Al(2)O(3) frame (H-Cu-Al/BC) for the removal of ammonium nitrogen (NH(4) (+)-N) from aqueous solutions. The as-synthesized samples were characterized via XRD, SEM, BET and FTIR spectroscopy. The BET specific surface area of the synthesized H-Cu-Al/BC increased from 175.4 m(2) g(-1) to 302.3 m(2) g(-1) upon the incorporation of the Cu-Al oxide nanoparticles in the BC surface channels. The experimental data indicated that the adsorption isotherms were well described by the Langmuir equilibrium isotherm equation and the adsorption kinetics of NH(4) (+)-N obeyed the pseudo-second-order kinetic model. The static maximum adsorption capacity of NH(4) (+)-N on H-Cu-Al/BC was 81.54 mg g(-1), which was significantly higher than those of raw BC and H-Al/BC. In addition, the presence of K(+), Na(+), Ca(2+), and Mg(2+) ions had no significant impact on the NH(4) (+)-N adsorption, but the presence of Al(3+) and humic acid (NOM) obviously affected and inhibited the NH(4) (+)-N adsorption. The thermodynamic analyses indicated that the adsorption process was endothermic and spontaneous in nature. H-Cu-Al/BC exhibited removal efficiency of more than 80% even after five consecutive cycles according to the recycle studies. These findings suggest that H-Cu-Al/BC can serve as a promising adsorbent for the removal of NH(4) (+)-N from aqueous solutions.